PROTEIN AND MICROSATELLITE SINGLE-LOCUS VARIABILITY IN SALMO-SALAR L (ATLANTIC SALMON)

We describe genetic variation at three microsatellite single loci and six allozyme loci of seven natural Atlantic salmon populations from Ir eland and Spain. A comparison of genetic variability detected at both types of loci is performed. Also, the relative value of microsatellite single locus variability with regard to the identification of individ ual salmon populations is assessed. Microsatellite loci are shown to d isplay higher levels of variation than allozyme loci. Mean number of a lleles (6+/-1.53) and heterozygosity (0.46+/-0.04) at microsatellite l oci are greater than those found for allozymes (1.85+/-0.05 and 0.21+/ -0.03, respectively), and some microsatellite alleles appear to be spe cific for a location or geographical area. Allozyme and microsatellite variation show the same pattern of differentiation between population s with Irish and Spanish populations grouped into different clusters. However, greater values of genetic distance were found among microsate llite (D=0.0747+/-0.011) rather than among allozyme loci (D=0.0449+/-0 .008). These results provide evidence that microsatellite-based analys is of genetic variation will be useful in the identification of indivi dual populations of Atlantic salmon.